Web/JavaScript/Reference/statements/return

The return statement ends function execution and specifies a value to be returned to the function caller.

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Syntax

return [expression]; 

expression

The expression whose value is to be returned. If omitted, undefined is returned instead.

Description

When a return statement is used in a function body, the execution of the function is stopped. If specified, a given value is returned to the function caller. For example, the following function returns the square of its argument, x, where x is a number.

function square(x) {
   return x * x;
}
var demo = square(3);
// demo will equal 9

If the value is omitted, undefined is returned instead.

The following return statements all break the function execution:

return;
return true;
return false;
return x;
return x + y / 3;

Automatic Semicolon Insertion

The return statement is affected by automatic semicolon insertion (ASI). No line terminator is allowed between the return keyword and the expression.

return
a + b;

is transformed by ASI into:

return; 
a + b;

The console will warn "unreachable code after return statement".

Starting with Firefox 40, a warning is shown in the console if unreachable code is found after a return statement.

To avoid this problem (to prevent ASI), you could use parentheses:

return (
  a + b
);

Examples

Interrupt a function

A function immediately stops at the point where return is called.

function counter() {
  for (var count = 1; ; count++) {  // infinite loop
    console.log(count + 'A'); // until 5
      if (count === 5) {          
        return;
      }
      console.log(count + 'B');  // until 4
    }
  console.log(count + 'C');  // never appears
}

counter();

// Output:
// 1A
// 1B
// 2A
// 2B
// 3A
// 3B
// 4A
// 4B
// 5A

Returning a function

See also the article about Closures.

function magic() {
  return function calc(x) { return x * 42; };
}

var answer = magic();
answer(1337); // 56154

Specifications

Specification
ECMAScript (ECMA-262)The definition of 'Return statement' in that specification.

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
return	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 3	Opera Full support 3	Safari Full support 1	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 1	Samsung Internet Android Full support 1.0	nodejs Full support 0.1.100

Legend

Full support  

Full support

See also

• Functions
• Closures

return by Mozilla Contributors is licensed under CC-BY-SA 2.5.